1. Field of the Invention
The present invention relates to the control of operative mechanisms in engine actuated machines and, more particularly, refers to a device for operating the clutch or the brakes in motorcycles and cycles.
2. Description of the Prior Art
Motorcycle clutches are provided to engage a motorcycle engine to the transmission mechanisms when power transmission to the wheels are needed and to disengage the transmission from the wheels when the motorcycle is to be stooped. The clutch is generally operated through a cable formed by an outer sheath and an inner core, that is a cable of the type called a Bowden cable. The cable is connected to a manually operated lever pivotally mounted on a handle bar of the motorcycle.
An end of the clutch cable is connected to the clutch for actuating the plates of the clutch while an opposite end of the cable is connected to an anchoring point in the pivoting lever. An only one anchoring point is fixed to only one predetermined position in a cable connecting portion of the lever. Thus, a predetermined rotation of the clutch lever will always cause the clutch plates to move along the same distance for coupling and uncoupling the clutch. It is well known that the distance along which the clutch plates move varies with the plates wearing during the use. It is also known that many motorcycle drivers differ as to the best "sensitivity" that such motorcycle manually operated controls should have. Thus, some motorcyclists prefer "hard" clutch levers while others prefer to use "soft" levers. In addition, some drivers prefer a lever to be moved along an extended arc to cause the clutch plates to be engaged and disengaged while others prefer to have a sudden engagement or disengagement of the plates with a small lever stroke.
It would be therefore very convenient to have a mechanism to control the operation of a clutch in a motorcycle wherein the distance along which the clutch plates move and the "sensitivity" of the control could be easily and rapidly changed.
U.S. Pat. No. 4,232,565 to Leonhearth discloses a twist-grip cable control having cable movement parallel to the axis of the twist-grip rotation for controlling a motorcycle carburetor, an intermediate bell-crank lever being pivotally mounted within a housing with the inner portion of a Bowden cable connected to one arm of the lever, the other arm of the lever operatively engaging a pin radially extending from a rotatable twist-grip sleeve, the sleeve is manually operated by the motorcyclist to move the pivoting lever and actuate on the carburetor of the motorcycle, the lever having a plurality of orifices to fix the inner portion of the cable.
U.S. Pat. No. 1,606,099 to Rudolph discloses a device comprising the combination of a fulcrum base, a lever pivoted thereon, means for holding said lever in a plurality of positions, a wire-holding plug pivotally mounted on the lever, and means for adjusting the distance of the plug from the fulcrum without detaching the plug from the lever.
The above mentioned patents provide for the changing of the distance between a wire anchoring point and a fulcrum but both mechanisms are complex and can not be used to be applied to a motorcycle for operating the clutch thereof. None of the above patents suggest or disclose a mechanism applied to a clutch, particularly to a motorcycle clutch lever, for varying the "sensitivity" thereof, to make it "softer" or "harder" or to easily adjust the lever stroke to the wearing of the clutch plates.